Research On System Design And Key Node Of Rectangular-section Cold-formed Steel Fabricated Structure

Fabricated steel structure has been widely used in China.As a kind of fabricat-ed steel structure,cold-formed thin-walled light steel structure is widely used due to its characteristics of light weight,high strength,good seismic performance,high space utilization and convenient construction.Commonly used light steel structures use open-section steels,and closed-section steels are less used.The main reason is that such steel joints are not easy to connect.At present,the existing joint connection schemes are mostly welded,and it is difficult to achieve assembly.Since the closed section steel itself has good mechanical properties and has great potential as a structural member of the structural system,it is of great significance to use such steel as a basic component.In this paper,a fabricated rectangular tube light steel structure system is designed by using cold-formed thin-walled closed-section steel as the basic component,and the mechanical properties of the key joint connection scheme of this system are systematically studied.The following parts are completed:Firstly,the use of prefabricated modular concept,the use of cold bending thin-wall rectangular steel tube as the keel structure,cold bending thin-wall channel steel,Angle steel is used as auxiliary components,use of self-drilling screw with tapping screw,and core pulling rivets as the basic design a prefabricated rectangular pipe fittings light steel structure system,and according to the concrete design project of the local node link,to provide a reference for the practical engineering application.Secondly,the static load test of full-size specimen is carried out for beamcolumn joints,and its full-size joint static load test is designed in detail.Completed five groups of prefabricated light steel rectangular tube node process of static load test,all nodes of the experimental phenomena are summarized,analyzed the overall deformation and failure mechanism of each node,the node stress law of development,the key parts are bending moment-rotation curve of each node,the node rotating mechanical properties such as the initial stiffness and ultimate bearing capacity index,compares the different form of light steel fittings and different node size of bearing capacity and stiffness.Thirdly,by means of numerical simulation,the static loading of the nodes is simulated,the deformation and stress development rules of the nodes in the loading process are analyzed,and the simulation results are compared with the test results to verify the feasibility of the simulation method.Parameter analysis method is used to analyze the parameters that affect the performance of joints,such as the thickness of components,the diameter of rivets,the number of rivets,etc.The influence law of the above parameters on the bearing capacity and stiffness of joints is obtained,and the improvement scheme of joints is proposed,which can be used for reference in practical application.